1. Field of the Invention
This invention relates generally to permanent magnets and more particularly to an advanced animal pill type magnet for improved collecting of iron bearing debris in the stomach of farm animals.
2. Description of Related Art
The following art defines the present state of this field:
Ogata, U.S. Pat. No. 5,096,763 describes a magnet article for attracting foreign matters in the stomach that is constituted by a hollow cylindrical case made of a corrosion-resistant, non-magnetic material: a plurality of disc-shaped yokes made of a soft magnetic material; a plurality of disc-shaped magnet members made of an R-Fe-B permanent magnet material and having magnetic poles on both end surfaces, the disc-shaped yokes in the hollow cylindrical case such that the magnetic poles having the same polarity of the adjacent disc-shaped magnet members face each other via each disc-shaped yoke; and a pair of end covers made of a corrosion-resistant, non-magnetic material, each end cover being fixed to each end of the hollow cylindrical case so that the inside of the hollow cylindrical case is sealed.
Mozis et at., U.S. Pat. No. 4,992,768 describes a cow magnet to be ingested by a ruminant animal comprises a stack of cylindrical permanent magnets having intermediate disk-like spacers of a soft magnetic material where the stack is held together by first and second plastic end cap members with integrally formed tubular sleeves adapted to fit into central bores formed through the cylindrical magnets and spacers with a predetermined friction fit. A pin formed from high carbon steel is then inserted down the center of the tubular sleeves to cause them to expand and tightly engage the side wall defining the central bore formed through the stacked arrangement of magnet and spacers.
Vars, U.S. Pat. No. 4,303,062 describes a therapeutic magnet for retention in the stomach of an animal comprises a plastic coated sintered ceramic magnet. The magnet is elongate and of uniform rectangular cross section in planes transverse to its principal dimension. The direction of magnetization is transverse to the principal dimension. The plastic coating serves to retain the separate parts of the magnet in the event of inadvertent fracture of the magnet.
Fujisawa, U.S. Pat. No. 4,283,698 describes a magnet device for collecting scrap irons in the stomach that which cattle have swallowed into the stomach. The magnet device is constituted by a plurality of magnets and at least a magnetic plate interposed therebetween.
Tarachand, U.S. Pat. No. 4,544,904 describes a composite permanent magnet and a circuit which employs a plurality of such magnets. The composite magnet combines discrete sections of a first magnet material with at least one discrete section of a second magnetic material. The first material has a high residual magnetic strength and a moderate energy product. The second material is many times more expensive than the first material and is characterized by a high residual magnetic strength and a high energy product.
Moriya, U.S. Pat. No. 3,206,657 describes a magnet assembly for filtering and to an assembly of discrete magnets adapted to be placed in a fluent material to extract paramagnetic particles therefrom. An object of this invention is the provision of the filter trap for paramagnetic particles which comprise spaced apart discrete magnets arranged in a sheath of non-magnetic material. Another object is the provision of a plurality of ball or short bar magnets arranged in spaced apart relation in a flexible sheath of non-magnetic material.
The prior art teaches the use of cow magnets for use in collecting debris in animal stomachs. However, the prior art does not teach the placement of the magnetic members in such magnets so that sharp objects tend not to collect at the ends of such devices, and do not teach how to obtain a ball shape as the debris builds-up on the device over time. The ball shape is preferred in minimizing the potential for stomach punctures from the sharp ends of such collected objects. The present invention fulfills these needs and provides further related advantages as described in the following summary.